|Budget Amount *help
¥2,200,000 (Direct Cost : ¥2,200,000)
Fiscal Year 1997 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1996 : ¥1,500,000 (Direct Cost : ¥1,500,000)
Metal-metal bonded small-size clusters of platinum and palladium have been of increasing interest as minimal models for the surface of heterogeneous catalysts ; structures, properties, and reactivities are able to be modified by varying the synthetic strategy and the choice of organic ligands. Systematic syntheses of homo- and heterotrimetallic platinum clusters through diplatinum precursors with bis (diphenylphosphino m ethyl) phenyl phosphine (dpmp) are reported. The reaction of [Pt_2(RNC)_6]^<2+> (RNC=aromatic isocyanide) with dpmp afforded an isomeric mixture of syn- and anti-[Pt_2(dpmp)_2(RNC)_2]^<2+> (syn-1 and anti-2). The differential reactivity of syn-1 and anti-2 allows an access to versatile aggregations of homo and hetero trinuclear clusters. The former (syn-1) was transformed by treatment with Pt^0, Pt^<II>, Pd^0, Pd^<II>, Rh^I, Ir^I, Au^I, Ag^I, and Cu^I species to a wide variety of Pt-Pt-M clusters, linear-[Pt_2(dpmp)_2(RNC)_2]^<2+> (M=Pt, Pd), asym-A-frame-[Pt_2MCl_2(dpmp)_2(RNC)_2]^<2+> (M=Pt, Pd), T-shape-[Pt_2MCl(dpmp)_2(RNC)_2]^<2+> (M=Ir, Rh), Y-shape-[Pt_2M(dpmp)_2(RNC)_2]^<3+> (M=Au, Ag), and rhombic-[Pt_2CuX(dpmp)_2]^<2+> (X=Cl, Br, I). Treatment of complex anti-2 with Pt^0 and Pd^0 species gave Pt-Pt-Pt and Pt-Pd-Pt A-frame clusters. The inserted position of an additional metal was interestingly regulated by the arrangements of two uncordinate phosphine units of 1 and 2. Di- and trinuclear plladium and molybdenum complexes with dpmp were also prepared and characterized.